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From Ishan Chhabra <ichha...@rocketfuel.com>
Subject Interaction of SequenceID and timestamps
Date Tue, 14 Jan 2014 23:26:11 GMT
I am trying to understand the interaction of sequenceId and timestamps for
KVs, and what was the real issue behind
https://issues.apache.org/jira/browse/HBASE-6590 which says that bulkload
can be used only to update only historical data and not current data.

Taking an example:

Lets say I have a KV (r, c, val1, 10), where 10 is the timestamp already in
Now, if I bulkload a KV (r, c, val2, 20) without the patch, will that be
sorted behind the previous KV since the file created has a sequenceID 0, or
will it be correctly be the new returned value during a scan for the (r,c).

I conducted some experiments myself and concluded that timestamp has a
priority over sequenceId and sequenceId is used to break a tie only when
the timestamp is the same, but I need to make sure that my understanding is


*Ishan Chhabra *| Rocket Scientist | RocketFuel Inc.

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